Search PubMed⌕ Search

Biomedical subjects

S Bryan

Publications and source records attributed to S Bryan.

At least 19 recordsLinked to original sources
PubMed2003

The use of hyaluronan and its sulphated derivative patterned with micrometric scale on glass substrate in melanocyte cell behaviour.

Surface microfabrication techniques were widely utilised for the spatial control of in vitro cell behaviour. A photo-immobilisation procedure was utilised to create micropatterned surfaces: four different stripe patterns (100, 50, 25 and 10 microm) of hyaluronan (Hyal) and its sulphated derivative (HyalS) on silanised glass substrate were obtained.The morphological analysis showed that the surface topography showed regular stripes of 100, 50, 25 and 10 microm wide and ranging from 300 nm up to 1 microm in thickness. They reproduced the exact photo-mask pattern: glass stripes alternating with polysaccharide ones. On the contrary, Hyal microstructures showed just a topographic pattern as the glass stripes appeared to be covered by a thin layer of the macromolecule by TOF-SIMS. Cell adhesion studies demonstrated that melanocytes adhered and oriented within the first 2h of culture on HyalS microdomains and not on Hyal microstructures where they spread on glass substrate around the patterned area. Double photo-immobilised samples characterised by a 100 microm stripe pattern of Hyal or HyalS on the top of a continuous layer of the two polysaccharides were also created in order to investigate the effect of the topography on cell behaviour. The obtained results demonstrated that melanocytes adhered on HyalS stripes while on the Hyal micropatterned surfaces they spread on silanised glass substrate around the structured area, resulting in the exclusion of the topographic pattern.

Animals↗
PubMed2002

Patterns, costs and cost-effectiveness of care in a trial of chemotherapy for advanced non-small cell lung cancer.

In a recently published randomised trial of chemotherapy versus palliative care in advanced non-small cell lung cancer (the MIC2 trial), chemotherapy was shown to prolong survival without compromising quality of life. The study presented here examines patterns of care and their associated costs within a representative subgroup of patients from the MIC2 trial. The study consisted of 116 patients from the South Birmingham Health Authority area. The total health service cost for each patient from entry to trial to death or last follow-up was calculated by combining the resources used with their associated unit costs. The mean cost for patients with complete data on the chemotherapy arm was 6999 pounds sterling (standard deviation (S.D.) 4194 pounds sterling) compared to 4076 pounds sterling (S.D. 3078 pounds sterling) for those with complete data on the palliative care arm. Non-parametric bootstrapping gave a difference between treatment arms in mean cost of 2924 pounds sterling(95% CI 1234 pounds sterling - 4323 pounds sterling). With a difference in mean survival of 2.4 months, this translates to an incremental cost-effectiveness ratio of 14,620 pounds sterling per life year gained. Chemotherapy was found to be more costly than standard palliative care, mainly due to the increased number of hospital in-patient days.

Aged↗
PubMed2001

EQ-5D in patients with dementia: an investigation of inter-rater agreement.

BACKGROUND: There are difficulties in obtaining health-related quality of life (HRQL) data from patients with dementia due to variation in their cognitive ability, degree of insight and capacity to make judgments. The use of proxies is one solution. OBJECTIVES: To examine the inter-rater agreement of patient and proxy completion of the EuroQol EQ-5D instrument (EQ-5D). RESEARCH DESIGN: The EQ-5D instrument was completed separately by patients, their caregivers and a physician. Assessment of inter-rater agreement involved comparison of self-completed (patient) and proxy-completed (caregiver and physician) responses for each dimension of EQ-5D, using a weighted kappa score. Three key hypotheses were tested. (1) Interrater agreement would be stronger between patient and caregiver than between patient and physician. (2) Interrater agreement would be stronger on the 'observable' and objective dimensions of EQ-5D. (3) Interrater agreement between patient and proxies would be stronger for patients with earlier dementia. SUBJECTS: The sample comprised 64 patients with a range of dementia severity. MEASURES: The EQ-5D health state classification system and visual analogue scale were used to assess HRQL. Global severity of dementia was determined using the Clinical Dementia Rating Scale. RESULTS: The principal finding of this study was that responses to EQ-5D questions were highly variable across the three raters such that none of the three hypotheses were strongly supported. CONCLUSIONS: The data provide some support for the use of EQ-5D when interviewer administered. However, there are serious concerns regarding the validity of patient self-rated HRQL data obtained in this study and uncertainty exists regarding who the appropriate proxy should be, as different groups of proxies provide different results. It was not clear whether caregivers or physicians represent better proxies. Further research should focus on the comparison of caregivers and physicians as proxies.

Activities of Daily Living↗
PubMed2001

The cost-effectiveness of magnetic resonance imaging for investigation of the knee joint.

OBJECTIVES: This study considered the role of magnetic resonance imaging (MRI) in the diagnosis of knee injuries in a district general hospital (DGH) setting. The principal objective was to identify whether the use of MRI had a major impact on the clinical management of patients presenting with chronic knee problems, in whom surgery was being considered, whether it reduced overall costs and whether it improved patient outcome. In addition, the research: (1) explored the 'diagnostic accuracy' of initial clinical investigation of the knee by an orthopaedic trainee, consultant knee specialist and consultant radiologist; (2) considered the variability and diagnostic accuracy of interpretations of knee MRI investigations between radiologists; (3) measured the strength of preference for the potential diagnostic/therapeutic impact of knee MRI (i.e. the avoidance of surgery). METHODS - RANDOMISED CONTROLLED TRIAL: The research was based on a single-centre randomised controlled trial conducted at Kent and Canterbury Hospital. Patients attending with knee problems in whom surgery was being considered were recruited from routine orthopaedic clinics. Most patients had been referred by their general practitioner. Patients were randomised to either investigation using an MRI scan (MRI trial arm) or investigation using arthroscopy (no-MRI trial arm). The study investigated the benefits of knee MRI at two levels: diagnostic/therapeutic impact (i.e. avoidance of surgery) and patient outcome (using the Short Form with 36 items and EQ-5D quality-of-life measurement instruments). Quality of life was assessed at baseline and at 6 and 12 months. Costs were assessed from the perspectives of the NHS and patients. All analyses were by intention to treat. METHODS - SUBSTUDIES (INVESTIGATION OF DIAGNOSTIC ACCURACY): For the investigation of diagnostic accuracy of initial clinical investigation, the sample comprised 114 patients recruited in a separate study conducted at St Thomas' Hospital. The sample was drawn from patients presenting at the Accident and Emergency Department with an acute knee injury. All study patients received an MRI scan, but initial diagnosis was made without access to the scan or the radiologist's report. After 12 months, all clinical notes and MRI scans of study patients were reviewed and a final 'reference standard' diagnosis for each patient was reached. Comparison was made between the diagnosis recorded by each clinician (i.e. orthopaedic trainee, knee specialist and consultant radiologist) and the reference diagnosis. METHODS - SUBSTUDIES (INVESTIGATION OF THE GENERALISABILITY OF RESULTS): For this substudy, the MRI images from 80 patients (recruited at St Thomas' Hospital) were interpreted independently by seven consultant radiologists at DGHs and the St Thomas' Hospital MRI radiologist. For each area of the knee, the level of agreement (measured using weighted kappa) between the responses of the eight radiologists and the reference standard diagnosis was assessed. METHODS - SUBSTUDIES (INVESTIGATION OF PREFERENCES): The investigation of potential patient preferences for the diagnostic/therapeutic impact of MRI was explored using a discrete choice conjoint measurement research design. Choices involved selecting between two alternative scenarios described using four attributes, and data were collected from 585 undergraduate sports science students and analysed using a random-effects probit model. RESULTS - RANDOMISED CONTROLLED TRIAL: The trial recruited 118 patients (59 randomly allocated to each arm). The two groups were similar in important respects at baseline. The central finding was of no statistically significant differences between groups in all measures of health outcome, although a trend in favour of the no-MRI group was observed. However, the use of MRI was found to be associated with a positive diagnostic/therapeutic impact: a significantly smaller proportion of patients in the MRI group underwent surgery (MRI = 0.41, no-MRI = 0.71; p = 0.001). There was a similar mean overall NHS cost for both groups. RESULTS - SUBSTUDIES (INVESTIGATION OF DIAGNOSTIC ACCURACY): The exploration of diagnostic accuracy found that, when compared to orthopaedic trainees (44% correct diagnoses) or to radiologists reporting an MRI scan (68% correct diagnoses), the accuracy rate was higher for knee specialists (72% correct diagnoses). RESULTS - SUBSTUDIES (INVESTIGATION OF THE GENERALISABILITY OF RESULTS): This generalisability study indicated that, in general terms, radiologists in DGHs provide accurate interpretations of knee MRI images that are similar to a radiologist at a specialist centre. The one area of the knee for which this did not hold was the lateral collateral ligament. RESULTS - SUBSTUDIES (INVESTIGATION OF PREFERENCES): The central finding for this substudy was that, on average and within the range specified, choices in this group of potential patients were not significantly influenced by variation in the chance of avoiding surgery. CONCLUSIONS - IMPLICATIONS FOR HEALTHCARE: The evidence presented in this report supports the conclusions that the use of MRI in patients presenting at DGHs with chronic knee problems in whom arthroscopy was being considered did not increase NHS costs overall, was not associated with significantly worse outcomes and avoided surgery in a significant proportion of patients. CONCLUSIONS - RECOMMENDATIONS FOR FURTHER RESEARCH (IN PRIORITY ORDER): (1) The trial data demonstrated that the use of MRI in patients with chronic knee problems reduced the need for surgery. However, the link between diagnostic processes and changes in health outcome is indirect and the finding of no-MRI-related effect on health outcome may, therefore, be a consequence of the limited power of the trial. Further research to confirm (or contradict) these findings would be valuable. (2) The investigation of diagnostic accuracy involved comparison with a reference diagnosis established by a panel of two clinical members of the research team. It would be interesting to explore the extent to which the results would differ using an external panel. (3) The result from the preference study, indicating that the potential diagnostic/therapeutic impact of knee MRI was not highly valued, is a surprising finding that would be important to explore in general public or patient populations. (4) The focus for the trial-based aspects of this research was the DGH and patients presenting with chronic knee problems who were being considered for surgery. Care should be taken in generalising from these results to other patient groups (e.g. acute knee injuries) or to other settings (e.g. specialist centres). Further clinical trials would be required in order to answer such questions.

Adolescent↗
PubMed2001

Patient costs in anticoagulation management: a comparison of primary and secondary care.

BACKGROUND: The demand for anticoagulation management is increasing. This has led to care being provided in non-hospital settings. While clinical studies have similarly demonstrated good clinical care in these settings, it is still unclear as to which alternative is the most efficient. AIM: To determine the costs borne by patients when attending an anticoagulation management clinic in either primary or secondary care and to use this information to consider the cost-effectiveness of anticoagulation management in primary and secondary care, both from the National Health Service and patient perspectives. DESIGN OF STUDY: Observational study comparing two cohorts of patients currently attending anticoagulation management clinics. SETTING: Four primary care clinics in Birmingham and one in Warwickshire, and the haematology clinics at the University of Birmingham Hospitals Trust and the City Hospital NHS Trust. METHOD: The survey of patients attending the clinics was used to ascertain patient costs. This information was then used in conjunction with the findings of a recent randomised controlled trial to establish cost-effectiveness. RESULTS: Patient costs were lower in primary care than in secondary care settings; the mean (standard deviation) costs per visit were Pound Sterling6.78 (Pound Sterling5.04) versus Pound Sterling14.58 (Pound Sterling9.08). While a previous cost-effectiveness analysis from a health sector perspective alone found a higher cost for primary care, the adoption of the societal perspective lead to a marked change in the result: a similar total cost per patient in both sectors. CONCLUSION: There are significantly higher costs borne by patients attending secondary care anticoagulation management clinics than similar patients attending primary care clinics. This study also demonstrates that the perspective adopted in an economic evaluation can influence the final result.

Aged↗
PubMed2000

Preference measurement using conjoint methods: an empirical investigation of reliability.

The application of conjoint measurement to the field of health economics is relatively new, although there is growing interest and there have been a number of studies undertaken recently. Wider acceptance of the technique requires methodological issues concerning both reliability and validity to be addressed. This paper reports an empirical investigation of the test-retest reliability of the discrete choice conjoint measurement approach in health care. This investigation of conjoint reliability was framed using the clinical context of investigation and treatment of knee injuries. A high level of reliability at both the input data and results levels was demonstrated.

Adolescent↗
PubMed2000

A comparison of the time required by radiologists for the preparation of clinico-radiological meetings when film and PACS are used.

The hypothesis was that when a hospital-wide Picture Archive and Communications System (PACS) is used, preparation for clinico-radiological meetings is faster, and more images are available, than when a conventional film system is used. This paper reports a study which compared the preparation time by radiologists when film was used with the time for the same activity when a hospital-wide PACS was used at Hammersmith Hospital for the preparation of the respirator medicine and hepato-biliary meeting. It was found that when PACS was used the time per patient to prepare for the respiratory medicine session was reduced by 11.1 min and that similarly, 16 min per patient was saved in the preparation of the hepato-biliary sessions. The number of images which were unavailable for the session was reduced when PACS was in operation, but this reduction was not shown to be statistically significant. The introduction of PACS at Hammersmith Hospital has significantly reduced the time spent by radiologists in preparing for the two clinico-radiological sessions studied and, if this is extended to the other numerous sessions held each week, contributes to a considerable saving of staff time within the radiology department.

Communication↗
PubMed2000

The impact of a picture archiving and communication system (PACS) upon an intensive care unit.

OBJECTIVE: The aim of the study was to assess the effect of the introduction of PACS (Picture Archiving and Communication System) upon image availability in an Intensive Care Unit (ICU) and the consequent impact upon the behaviour of the ICU physicians, in terms of the initiation of image-based clinical actions. DESIGN: A before and after study was used to compare the speed of image availability prior to, and following, the implementation of a hospital-wide PACS. SETTING: The research was part of an economic evaluation of PACS at Hammersmith Hospital, West London. PATIENTS AND PARTICIPANTS: All ICU patients who were X-rayed during two pre-PACS and one post-PACS data collection periods were included within the study. MEASUREMENTS: The times of: the X-ray request; acquisition; availability on ICU; and of any image-based clinical action taken by the ICU physician were recorded by radiographers and ICU physicians. RESULTS: PACS significantly reduced the time between request and image availability on ICU for routine X-rays but did not have any measurable impact upon the time clinical actions were initiated by ICU physicians. The data on non-routine images were statistically inconclusive. CONCLUSIONS: This study shows that PACS significantly improves the speed of delivery of routine images to the ICU, but it appears that the instigation of image-based clinical actions is determined by other organisational factors in ICU, such as ward rounds, rather than the availability of the image for viewing. Further work is required on non-routine X-rays to clarify the impact of PACS on physician behaviour in clinically urgent situations.

Humans↗
PubMed2000

Estimating the impact of a diffuse technology on the running costs of a hospital. A case study of a picture archiving and communication system.

OBJECTIVES: This paper considers the methodological problems that arise in conducting cost analyses in economic evaluations where only observational (rather than experimental) data are available and where the technology being evaluated is diffuse, such that the unit of analysis has to be the institution rather than the patient. METHODS: A case study is reported that concerns the application of computer technology in radiology: picture archiving and communication systems (PACS). A range of different approaches were used to estimate changes in running costs, including time series analyses of routine data and direct observation of resource use. RESULTS: The analysis illustrates some of the difficulties involved in costing the introduction of a diffuse technology. Nevertheless, it provides a firm indication that, overall, the introduction of PACS was found to be associated with a significant increase in hospital costs, suggesting that the initial expectations of financial savings were unduly optimistic. CONCLUSIONS: The research demonstrates that, using multiple methods, it is possible to estimate cost changes within a single hospital. In addition, the paper discusses the nature of the uncertainties in such analyses and possible ways of representing such uncertainty in terms of confidence intervals.

Budgets↗
PubMed2000

The effect of a picture archiving and communications system (PACS) on diagnostic performance in the accident and emergency department.

OBJECTIVE: A study has been conducted to identify the benefits to the accident and emergency (A&E) department of a hospital wide Picture Archiving and Communications System (PACS). METHODS: The study was conducted in two parts: firstly while the hospital was using conventional radiographic films, and secondly when the PACS was in operation. For each part of the study, the diagnoses of radiographic images made by A&E clinicians were compared with those made by radiologists. This resulted in the estimation of the incidence of false negative findings by the A&E staff. The management of patients with such findings was studied to identify those for whom a change of treatment was required. Such data for the two periods, when film and when PACS was used, were compared. RESULTS: It was found that the overall rate of misdiagnoses across all A&E patients who had radiography was low in both periods and there was a significant reduction when PACS was used (1.5% for film and 0.7% for PACS, 95% CI for difference between proportions: -0.014 to -0.0034), but the rate of serious misdiagnoses involving patient recall did not change significantly (95% CI for difference between proportions: -0.0059 to +0.0001). CONCLUSIONS: When PACS was used the diagnostic performance by A&E staff improved by reducing false negative interpretations but the rate of serious misdiagnosis did not change.

Diagnostic Errors↗